Changes in lipid composition and some biologically important enzyme activities in the microsomal membranes of developing toad ovary in different seasons.

ABSTRACT

The microsomal membranes isolated by sucrose density gradient centrifugation from developing toad ovary have been found to differ significantly in lipid composition and various enzyme activities in different seasons. All the enzymes studied, viz. Na+, K(+)-ATPase, delta 5-3 beta-hydroxysteroid dehydrogenase (delta 5-3 beta HSD) and prostaglandin synthetase, exhibited maximum activity during the breeding season (July-September) at all stages of development (a,b,c & d). The activities of Na+, K(+)-ATPase and delta 5-3 beta HSD increased with development while that of prostaglandin synthetase followed the reverse order. The total phospholipid, cholesterol and fatty acid contents also varied with season and development. The increase in Na+, K(+)-ATPase and delta 5-3 beta HSD activities in the microsomal membranes of toad ovary at breeding season is accompanied with concomitant increase in phospholipid and unsaturated fatty acid contents at different stages in this season, thereby suggesting some correlation between them.